The Flow Cytometry Core Facility provides a broad range of applications to Rheumatic Disease Core Center Members including but not limited to the following: light scatter measurements assessing cell volume and structural differences;single and multiple intracellular and/or surface immunofluorescence measurements; DNA ploidy measurements and cell cycle analysis;functional measurements of cellular calcium and potassium flux and oxidative burst;detection and quantitation of apoptotic cell death, incident polarization study;cell sorting on any or a combination of several analytical criteria. The Flow Cytometry Core Facility is currently located in the University of Michigan's Cancer and Geriatrics Center's building and has been in continuous operation under the direction of Dr. Robert Todd since October 1984. Investigators deliver pre-processed samples to the Core for flow cytometric analysis and/or cell sorting. Instruments are operated by trained flow cytometry operators (4.4 FTEs). Core instrumentation includes a BD Biosciences FACSVantage SE multilaser high-speed cell sorter, two BD Biosciences FACSDiVa multilaser high-speed cell sorters, a BD Biosciences FACSAria multilaser high-speed cell sorter, a BD Biosciences FACSCalibur multilaser analyzer and a Beckman-Coulter EPICS XL analyzer. UM-RDCC members (28 of 257) account for approximately 35% of total use of the core.